PropertyIsNull.h

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/*  Copyright (C) 2008 National Institute For Space Research (INPE) - Brazil.
 
    This file is part of the TerraLib - a Framework for building GIS enabled applications.
 
    TerraLib is free software: you can redistribute it and/or modify
    it under the terms of the GNU Lesser General Public License as published by
    the Free Software Foundation, either version 3 of the License,
    or (at your option) any later version.
 
    TerraLib is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    GNU Lesser General Public License for more details.
 
    You should have received a copy of the GNU Lesser General Public License
    along with TerraLib. See COPYING. If not, write to
    TerraLib Team at <terralib-team@terralib.org>.
 */
 
/*!
  \file PropertyIsNull.h
  
  \brief The PropertyIsNull class encodes an operator that checks to see if the value of its content is NULL.
 */
 
#ifndef __TERRALIB_FE_INTERNAL_PROPERTYISNULL_H
#define __TERRALIB_FE_INTERNAL_PROPERTYISNULL_H
 
// TerraLib
#include "ComparisonOp.h"
 
namespace te
{
  namespace fe
  {
// Forward declarations
    class PropertyName;
 
    /*!
      \class PropertyIsNull
      
      \brief The PropertyIsNull class encodes an operator that checks to see if the value of its content is NULL.
 
      A NULL is equivalent to no value present. The value 0 is
      a valid value and is not considered NULL.
 
      \ingroup fe
 
      \sa ComparisonOp, PropertyName
     */
    class TEFEEXPORT PropertyIsNull : public ComparisonOp
    {
      public:
 
        TE_DEFINE_VISITABLE
 
        /** @name Initializer Methods
         *  Methods related to instantiation and destruction.
         */
        //@{
 
        /*! \brief It initializes a new PropertyIsNull. */
        PropertyIsNull();
 
        /*! \brief Destructor. */
        ~PropertyIsNull();
 
        //@}
 
        /** @name Accessor methods
         *  Methods used to get or set properties.
         */
        //@{
 
        /*!
          \brief It sets the property name.
 
          \param p The property name.
 
          \note It will take the ownership of the property name.
         */
        void setPropertyName(PropertyName* p);
 
        /*!
          \brief It returns the property name.
 
          \return The property name.
         */
        PropertyName* getPropertyName() const;
 
        //@}
 
         /*! \brief It creates a new copy of this object. */
        ComparisonOp* clone() const;
 
 
      private:
 
        PropertyName* m_property;  //!< Mandatory.
    };    
 
  } // end namespace fe
}   // end namespace te
 
#endif  // __TERRALIB_FE_INTERNAL_PROPERTYISNULL_H